Feedebic schaefeb



(No Model.)

P. SCHABFBR.

MANUPAGTURB 0F PILAMBNTS POR INGANDESGENT LAMPS.

N0. 320,297. Patented June'l, 1885.

N. Pimm Pmurummprw. waning .c.

u which will carbonize substantially in unison an STATES FREDERIC SCHAEFER, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO LEOPOLD SOHLEGELMILCH, TRUSTEE, OF SAME PLACE.

MANUFACTURE OF FILAIVIENTS FOR INCANDESCENT LAMPS.

SPECIFCATION forming part of Letters Application filed November Q6, 1884.

Patent No. $520,297, dated June 16, 1885.

(No model.)

To all whom t may concern Beit known that I, FREDERIC SCHAEFER, of Boston, county of' Suffolk, and State of Massachusetts, have invented an Improvement in Manufacture of Filaments for Electric Lamps, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawingsrepresenting like parts.

The object of this invention is to facilitate and cheapen the manufacture of filaments for electric lamps, as well as to improve the product. A s heretofore usually practiced, the fila- 1ne11ts,\vliich are very slender and delicate, and require careful handling, have been shaped and carbonized singly, each onehaving a separate mold or occupying a separate recess in a compound mold to retain it inthe proper shape While being carbonized; or they have been carbonized on a solid unyielding former made of carbon or graphite.

In accordance with my present invention, a large nu mber-several hundreds, if desiredof filaments may be shaped and carbonized at a single operation and in a very short time.

ln accordance with my invention, filaments to be carbonized are Wrapped or Wound about a flexible or yielding former, preferably While the said former is held upon or supported internally by a mold shaped to correspond in crosssection with the shape desired for the carbouized iilament, the said former, the filaments having` been wound thereon, being removed i'rom the mold and then placed in a retort or Crucible, where the former and the laments thereon are subjected to heat and carbonizcd, the said former within the filament carbonizing and shrinking in unison with the filaments, thus obviating all strain upon the same, leaving the carbonized filaments unbroken upon the carbonizcd former, ready t0 be cut off desired.

In accordance with my invention,theformer composed of paper, cloth, or other material with or shrink to substantially the same degree as the thread filaments when the latter are being carbonized. I select for the production of nxy former a carbonizable flexible material, in order that it may be bent into any d esi red shape, and if the material selected is not sufficiently stiff to retan its shape it may be sti ffened by stiffening material-such as Wax-so as to retain the shape given to it. The thread to be carbonized will preferably be Wound on the former in successive turns, the thread being laid evenly and parallel, one turn by the side of the other. After carbonizing the former and the thread thereon the said thread may be cut or divided at proper places to enable the carbonized filaments to be removed as needed for use. If desired, the filaments may be retained on the light-weight carbonized former for storage or transportation.

Figure l is a side elevation of a former provided with a continuous thread or a series of turns of thread for the manufacture of filaments in accordance with this invention; Fig. 2, an end elevation thereof; Fig. 3, a side elevation of one of the finished filaments, and Figs. 4 and 5 modifications showingthe method of producing filaments of other shapes.

The yielding carbonizable former a may be made of the shape desired for the finished filaments, it being formed or shaped over a suitabie mold or die, which may be of wood or of any desired material. The yielding former a is itself composed of paper or cloth or similar flexible carbonizable material which may be easily shaped, and which is sufficiently stiff, or may be provided with stiffening, to cause itto retain its shape when the former is removed from the mold. Upon the said yielding carbonizable former a is Wound a thread, b,of sil k, cotton, or other material, of greater or less length, suitable for carboniziug and forming a carbon filament, the said thread, either before or after winding, being subjected to the usual processes practiced in preparing the same for carbonizing-sueh, forinstance, as saturating With sirup and applying pulver-ized carbon or other materials usually employed, although dry thread may be used Without other material. The successive turns of the thread I) are laid close to one another, so that they are substantially parallel and all of the same shape, and the entire series or turns of thread, together with the yielding former a after it shall have been removed from the mold, is subjected tov the usual carbonizing process by being embedded or inelosed in pulverized carbon or surrounded with pieces of carbon in an airtight boX or Crucible and subjected to strong heat, and, owing to its nature, the yielding former, which is carbonized at the same time as the thread, shrinks or contracts in unison withit. Whenthuscarbonized,thesuccessive turns of the thread bmay be broken or cut and separated from one another and from theformer, each of the said turns forming a complete filament, as shown at c, Fig. 3, the entire series being of uniform size, shape, and quality; or the threads upon the former as they are may be shipped at once. rIhe former, as the thread is carbonized, permits` the thread. to contract and prevents it from breaking.

This method may be employed for making filaments of any shape. Vhen, however, the :filament contains re-entering portions, as employed in some kinds of lamps, the former a, made, as hereinbefore described, of proper shape to lit the interior of the filament, will be provided, as shown in Fig. 4, with a block or support, d, over which the thread b will be wound, leaving each turn of the thread of sufficient length to fit the exterior of the former a, after which the block b willbe removed, and an outside carbonizableformer, a', (see Fig. 5,) corresponding in shape to the outline of the inner former, a, will be applied to thus retain the thread close upon thesurface of the former a, the said thread being carbonized whileheld between the inside and outside carbonizable formers, a a', as before described.

A carbonizable former, a, may be shaped at both ends like the rounded end of the oneshown in Fig. l, the thread after it shall have been carbonized being severed midway between the ends of the former, so that each turn of the thread around the former makes two complete filaments.

Thefilaments when thus made maybcplaced in a lamp-globe and be connected with platinum or other conductors passing'out through the same in any suitable or usual manner.

I do not claim ametallie former, nor a former containing metal in any way, for the heat necessary to properly carbonize the thread is greater than that required to melt ali metals, and therefore the metal would melt before the carbonizing of the thread was completed; nor do I claim carbonizing aiilament on a rigid or on a carbonized former of any shape.

I claiml. rIhat improvement in the art or method of manufacturing filaments for electric lamps which consists in laying athread overayielding carbonizable former, the said former receiving its shape from amold,whieh is removed from the former after the thread has been wound thereon, then simultaneously carbonizing the thread and former, whereby the moleeular structure of the thread ortlamentis in no way subjected to astrain, the former yielding in the carbonizing process, thus obviating the breaking of the iilaments, substantially as described.

2. That improvement in the art or method of manufacturing filaments for electric lamps which consists in laying a thread in aseries of turns over the surface of a yielding carbonizable former, and simultaneously carbonizing the thread and former located within it, thus preserving the thread upon the former in a convenient form for shipment, substantially as described.

` In testimony whereof Iliavesigned my name to this specification in thepresenceof twosubscribing witnesses.

FREDERIC SCHAEFER.

Vitnesses:

Jos. I). LIVERMORE, W. H. SIGsToN. 

